Lithium (Li) metal anode holds great promise for high-energy-density rechargeable batteries. However, it suffers from the Li dendrites growth and uncontrollable side reactions with electrolyte due to the unstable solid electrolyte interphase (SEI) layer. Herein, we propose a facile strategy for the in-situ fabricate of organic-inorganic composite artificial SEI layers on Li surfaces, which consist of organic fluorinated siloxane and inorganic LiF-rich phases. The hybrid artificial SEI endows high mechanical strength (13.1 GPa) and Li⁺ transfer number (0.62). Such robust SEI protective layers can not only guide uniform nucleation and deposition of Li metal by facilitating uniform Li-ion distribution, but also prevent unfavourable side reactions. Accordingly, the protected metallic lithium anode (PMTFPS-Li) anode enables stable Li plating/stripping performance in symmetric cells for more than 300 h at 4 mA ·h/cm² under a high areal capacity of 4 mA/cm². Moreover, the PMTFPS-Li/S cells could maintain more than 300 stable cycles at 0.5C and the PMTFPS-Li/LFP cells present excellent cycling performance (400 cycles at 1C) and enhanced rate capability (110.4 mA·h/g at 3 C). This work will inspire the design of artificial SEI on Li anodes for advanced Li metal batteries.

The sluggish kinetics of complicated multiphase conversions and the severe shuttling effect of lithium polysulfides (LiPSs) significantly hinder the applications of Li-S battery, which is one of the most promising candidates for the next-generation energy storage system. Herein, a bifunctional electrocatalyst, indium phthalocyanine self-assembled with carbon nanotubes (InPc@CNT) composite material, is proposed to promote the conversion kinetics of both reduction and oxidation processes, demonstrating a bidirectional catalytic effect on both nucleation and dissolution of Li₂S species. The theoretical calculation shows that the unique electronic configuration of InPc@CNT is conducive to trapping soluble polysulfides in the reduction process, as well as the modulation of electron transfer dynamics also endows the dissolution of Li₂S in the oxidation reaction, which will accelerate the effectiveness of catalytic conversion and facilitate sulfur utilization. Moreover, the InPc@CNT modified separator displays lower overpotential for polysulfide transformation, alleviating polarization of electrode during cycling. The integrated spectroscopy analysis, HRTEM, and electrochemical study reveal that the InPc@CNT acts as an efficient multifunctional catalytic center to satisfy the requirements of accelerating charging and discharging processes. Therefore, the Li–S battery with InPc@CNT-modified separator obtains a discharge-specific capacity of 1415 mAh g⁻¹ at a high rate of 0.5 C. Additionally, the 2 Ah Li–S pouch cells deliver 315 Wh kg⁻¹ and achieved 80% capacity retention after 50 cycles at 0.1 C with a high sulfur loading of 10 mg cm⁻². Our study provides a practical method to introduce bifunctional electrocatalysts for boosting the electrochemical properties of Li–S batteries.